/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
using java = biz.ritter.javapi;

namespace org.apache.commons.compress.archivers {

    /**
     * Archive input streams <b>MUST</b> override the 
     * {@link #read(byte[], int, int)} - or {@link #read()} -
     * method so that reading from the stream generates EOF for the end of
     * data in each entry as well as at the end of the file proper.
     * <p>
     * The {@link #getNextEntry()} method is used to reset the input stream
     * ready for reading the data from the next entry.
     * <p>
     * The input stream classes must also implement a method with the signature:
     * <pre>
     * public static boolean matches(byte[] signature, int length)
     * </pre>
     * which is used by the {@link ArchiveStreamFactory} to autodetect
     * the archive type from the first few bytes of a stream. 
     */
    public abstract class ArchiveInputStream : java.io.InputStream {

        private byte[] SINGLE = new byte[1];
        private static readonly int BYTE_MASK = 0xFF;
    
        /** holds the number of bytes read in this stream */
        private long bytesRead = 0;

        /**
         * Returns the next Archive Entry in this Stream.
         *
         * @return the next entry,
         *         or <code>null</code> if there are no more entries
         * @throws IOException if the next entry could not be read
         */
        public abstract ArchiveEntry getNextEntry();// throws IOException;

        /*
         * Note that subclasses also implement specific get() methods which
         * return the appropriate class without need for a cast.
         * See SVN revision r743259
         * @return
         * @throws IOException
         */
        // public abstract XXXArchiveEntry getNextXXXEntry() throws IOException;

        /**
         * Reads a byte of data. This method will block until enough input is
         * available.
         * 
         * Simply calls the {@link #read(byte[], int, int)} method.
         * 
         * MUST be overridden if the {@link #read(byte[], int, int)} method
         * is not overridden; may be overridden otherwise.
         * 
         * @return the byte read, or -1 if end of input is reached
         * @throws IOException
         *             if an I/O error has occurred
         */
        public override int read() //throws IOException 
        {
            int num = read(SINGLE, 0, 1);
            return num == -1 ? -1 : SINGLE[0] & BYTE_MASK;
        }
    
        /**
         * Increments the counter of already read bytes.
         * Doesn't increment if the EOF has been hit (read == -1)
         * 
         * @param read the number of bytes read
         */
        protected void count(int read) {
            count((long) read);
        }

        /**
         * Increments the counter of already read bytes.
         * Doesn't increment if the EOF has been hit (read == -1)
         * 
         * @param read the number of bytes read
         * @since Apache Commons Compress 1.1
         */
        protected void count(long read) {
            if (read != -1) {
                bytesRead = bytesRead + read;
            }
        }
    
        /**
         * Decrements the counter of already read bytes.
         * 
         * @param pushedBack the number of bytes pushed back.
         * @since Apache Commons Compress 1.1
         */
        protected void pushedBackBytes(long pushedBack) {
            bytesRead -= pushedBack;
        }
    
        /**
         * Returns the current number of bytes read from this stream.
         * @return the number of read bytes
         * @deprecated this method may yield wrong results for large
         * archives, use #getBytesRead instead
         */
        public int getCount() {
            return (int) bytesRead;
        }

        /**
         * Returns the current number of bytes read from this stream.
         * @return the number of read bytes
         * @since Apache Commons Compress 1.1
         */
        public long getBytesRead() {
            return bytesRead;
        }

        /**
         * Whether this stream is able to read the given entry.
         *
         * <p>Some archive formats support variants or details that are
         * not supported (yet).</p>
         *
         * <p>This implementation always returns true.
         *
         * @since Apache Commons Compress 1.1
         */
        public virtual bool canReadEntryData(ArchiveEntry ae) {
            return true;
        }

    }
}